SAMUL · A Novel Multi-Scale Microvascular and Functional Ultrasound Simultaneous Assessment of Heart-Brain Axis

The heart-brain axis (HBA) is a critically important bidirectional communication network that is essential for maintaining physiological equilibrium. Its dysregulation is a key pathological mechanism in disorders such as stroke, where an injury in one organ can precipitate secondary failure in the other, drastically worsening patient outcomes. A major obstacle is the technological gap that prevents from simultaneously imaging the heart and brain as an interconnected system; capturing their interactions at the microscopic scale where early microvascular pathophysiology begins. To address these, SAMUL (Simultaneous Acquisition of Microvascular and functional ULtrasound), aims to overcome this limitation by developing the integrated, non-invasive ultrasound technique for synchronized dual-organ assessment. The project will synchronize two research ultrasound scanners to acquire ultrafast data simultaneously from the heart and brain in rodents. It will interleave contrast-enhanced modes for super-resolution Ultrasound Localization Microscopy (ULM) with non-contrast functional Ultrasound (fUS) imaging (WP1). A unified computational pipeline will then be developed to generate co-registered, quantitative maps of microvascular architecture and organ function (WP2). This integrated platform will be rigorously validated in a longitudinal rodent model of ischemic stroke (WP3). The goal is to perform the first quantitative correlation analysis of neuro-cardiac coupling, linking imaging-derived parameters to early physiological symptoms to identify predictive biomarkers of HBA dysregulation. By providing a validated, open-source toolset, SAMUL will establish a new standard for multi-organ physiological investigation. This work is a critical first step that paves the way for future diagnostic applications, with the potential to transform patient care in neuro-ICUs and stroke units from a reactive to a proactive model through enabled early intervention.